Biology Reference
In-Depth Information
D ECAY , Bulb; internal. Enterobacter cloacae,
CA.
D ODDER . Cuscuta spp., widespread.
D OWNY M ILDEW .
R OT ,Smudge.Colletotrichum circinans,general.
R OT , Soft.
Kluyveromyces marxianus
var.
marxianus, OR, WA.
R OT , Various, of bulbs. Aspergillus niger, black
mold, general in market; Penicillium spp., blue
mold; Rhizopus stolonifer, soft, after sunscald
or freezing; Sclerotinia sclerotiorum, watery
soft; Fusarium proliferatum, bulb rot, WA.
R OT , White. Sclerotium cepivorum, CA, KY,
LA, ME, NJ, NY, OH, OR, PA, TX, VA.
R UST . Puccinia asparagi (0, I, II, III), CA,
CT, IA, KS, MN; P. allii ( P. porri ) (II, III),
CA, CT, NE.
S MUT . Urocystis cepulae, general; U. colchici.
T WISTER
Peronospora
destructor,
general.
L EAF B LIGHT ; Bulb Rot. Pantoea agglomerans,
GA.
L EAF N ECROSIS ; Seedling Death. Phytophthora
nicotianae, NM.
L EAF S POT . Heterosporium allii, CA, CO, WA;
Phyllosticta allii,
IL, NM; Stemphylium
vesicarium, TX.
N EMATODE , Bulb. Onion Bloat.
Ditylenchus
dipsaci, NY, TX.
N EMATODE , Root Knot. Meloidogyne incognita.
N EMATODE , Sting. Belonolaimus gracilis.
N EMATODE , Stubby Root.
D ISEASE .
Colletotrichum
gloeosporium,GA.
V IRUS . Onion Yellow Dwarf; Scape Blight
caused by Impatiens Necrotic Spot and
other Tospovirus isolate/strain, ID, including
Iris Yellow Spot, CO, GA, ID, NM, OR, TX,
WA (also on wild onions, Allium pskemense,
A. vavilovii, and A. altaicum); Iris Yellow
Spot, CA, CO, HI, GA, NY, NV, NM, OR,
TX, WA, Ontario, Canada, Uruguay.
Smut is the most general onion disease, but it
seldom afflicts onions grown from sets, the usual
method for a small garden. Growing colored
instead of white onions avoids smudge and neck
rots to some extent. Sweet Spanish onions are
resistant to pink root and yellow dwarf.
Paratrichodorus
christiei.
N ONPARASITIC . Blast, of inflorescence. Appears in
Connecticut Valley when bright sun follows
cloudy weather. Air pollution in NJ.
Chlorosis. Copper deficiency, FL, NY; Manga-
nese deficiency, NY, RI.
Scald. High temperature, general in summer.
Stain, alkali spot. Contact with alkaline materials
or ammonia fumes in transit.
P HYTOPLASMA . Aster Yellows, Clover Prolifera-
tion, TX.
P OWDERY M ILDEW . Oidiopsis taurica, CA;
Leveillula taurica, ID, Pacific Northwest.
R OT , Basal. Fusarium oxysporum f. sp. cepae,
other species, widespread.
R OT , Black Stalk, Tip Blight, Seed Mold.
Stemphylium botryosum, AR, CA, LA,
NH, TX, WA.
R OT , Bulb. Enterobacter cloacae,WA.
R OT , Charcoal. Macrophomina phaseoli, CA,
OK, TX.
R OT ,
Onosmodium (Marbleseed)
R OT , Root. Phymatotrichum omnivorum, TX.
R UST . Puccinia recondita (0,
I), CO, KS,
NE, ND.
Dry.
Diplodia
natalensis,
TX;
Oplismenus (Basket-grass)
Helminthosporium allii, also canker.
R OT , Neck; Gray Mold. Botrytis allii, CA, LA,
NJ, TX; B. cinerea; Small Sclerotial; Leaf
Blight, B. ( Botryotinia, Sclerotinia )
squamosa, occasional; B. porri,WA.
R OT , Pink Root. Pyrenochaeta terrestris,
widespread.
R OT , Root. Thielaviopsis basicola, TX.
L EAF S POT , Tar. Phyllachora punctum, FL, LA.
Orange
Citrus Fruits.
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